connectors/__init__.py
author Edouard Tisserant
Tue, 25 Aug 2020 14:32:39 +0200
branchsvghmi
changeset 3036 4930455428df
parent 2537 eb4a4cc41914
child 3501 fa291393aac7
permissions -rw-r--r--
SVGHMI: JsonTable now use intermediate variables again to address JSON data without duplicating code or referencing. Using intermediate variables also alows to check for availability of data and stop evaluating early if data is missing. Finally added complete roundtrip example to illustrate use of JSonTable to display "alarms" collected in python from changes on PLC boolean variables.
#!/usr/bin/env python
# -*- coding: utf-8 -*-

# This file is part of Beremiz, a Integrated Development Environment for
# programming IEC 61131-3 automates supporting plcopen standard and CanFestival.
#
# Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD
# Copyright (C) 2017: Andrey Skvortsov
#
# See COPYING file for copyrights details.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

# Package initialisation


from __future__ import absolute_import
from os import listdir, path
from connectors.ConnectorBase import ConnectorBase

connectors_packages = ["PYRO", "WAMP"]


def _GetLocalConnectorClassFactory(name):
    return lambda: getattr(__import__(name, globals(), locals()), name + "_connector_factory")


connectors = {name: _GetLocalConnectorClassFactory(name)
              for name in connectors_packages}

_dialogs_imported = False
per_URI_connectors = None
schemes = None


# lazy import of connectors dialogs, only if used
def _Import_Dialogs():
    global per_URI_connectors, schemes, _dialogs_imported
    if not _dialogs_imported:
        _dialogs_imported = True
        per_URI_connectors = {}
        schemes = []
        for con_name in connectors_packages:
            module = __import__(con_name + '_dialog', globals(), locals())

            for scheme in module.Schemes:
                per_URI_connectors[scheme] = getattr(module, con_name + '_dialog')
                schemes += [scheme]


def ConnectorFactory(uri, confnodesroot):
    """
    Return a connector corresponding to the URI
    or None if cannot connect to URI
    """
    _scheme = uri.split("://")[0].upper()

    # commented code to enable for MDNS:// support
    # _scheme, location = uri.split("://")
    # _scheme = _scheme.upper()

    if _scheme == "LOCAL":
        # Local is special case
        # pyro connection to local runtime
        # started on demand, listening on random port
        scheme = "PYRO"
        runtime_port = confnodesroot.AppFrame.StartLocalRuntime(
            taskbaricon=True)
        uri = "PYROLOC://127.0.0.1:" + str(runtime_port)

    # commented code to enable for MDNS:// support
    # elif _scheme == "MDNS":
    #     try:
    #         from zeroconf import Zeroconf
    #         r = Zeroconf()
    #         i = r.get_service_info(zeroconf_service_type, location)
    #         if i is None:
    #             raise Exception("'%s' not found" % location)
    #         ip = str(socket.inet_ntoa(i.address))
    #         port = str(i.port)
    #         newlocation = ip + ':' + port
    #         confnodesroot.logger.write(_("'{a1}' is located at {a2}\n").format(a1=location, a2=newlocation))
    #         location = newlocation
    #         # not a bug, but a workaround against obvious downgrade attack
    #         scheme = "PYROS"
    #         r.close()
    #     except Exception:
    #         confnodesroot.logger.write_error(_("MDNS resolution failure for '%s'\n") % location)
    #         confnodesroot.logger.write_error(traceback.format_exc())
    #         return None

    elif _scheme in connectors:
        scheme = _scheme
    elif _scheme[-1] == 'S' and _scheme[:-1] in connectors:
        scheme = _scheme[:-1]
    else:
        return None

    # import module according to uri type and get connector specific baseclass
    # first call to import the module,
    # then call with parameters to create the class
    connector_specific_class = connectors[scheme]()(uri, confnodesroot)

    if connector_specific_class is None:
        return None

    # new class inheriting from generic and specific connector base classes
    return type(_scheme + "_connector",
                (ConnectorBase, connector_specific_class), {})()


def EditorClassFromScheme(scheme):
    _Import_Dialogs()
    return per_URI_connectors.get(scheme, None)


def ConnectorSchemes():
    _Import_Dialogs()
    return schemes